5500 Series Rev D Pilot Operated Pressure Relief Vent With Pipe Away; Mates With ASME 150 Flange Connection; 6" Inlet Size; 8" Outlet Size; 316 Stainless Steel Body And Bolt-In Seat Ring; FEP Actuator Diaphragm With FFKM 2 Pilot Seat And FEP Pallet Diaphragms; 2.1" - 12.0" wc Pressure Spring Range With Air Assist; Standard: Internal Sensing With Pilot Exhaust To Main Valve Outlet And Backflow Preventer